In a wiring structure of a semiconductor device, electro migration (EM) is conventionally considered problematic as one defective mode. As a measure to suppress EM, a so-called support wiring is used. The support wiring is a wiring arranged in a second layer, for example, in a manner to be superposed on a power supply wiring of a first layer of a multilayer wiring structure, and electrically connected to a power supply wiring of an M1 layer. Provision of the support wiring reduces current in the power supply wiring, thereby suppressing occurrence of EM.
[Patent Document 1] U.S. Unexamined Patent Application Publication No. 2015/0248517
[Patent Document 2] U.S. Unexamined Patent Application Publication No. 2015/0052494
[Patent Document 3] U.S. Unexamined Patent Application Publication No. 2015/0286765
[Patent Document 4] U.S. Unexamined Patent Application Publication No. 2016/0035628
In recent years, to response to a need for further microfabrication of the semiconductor device, wiring formation using a so-called double patterning technique increases. In pattern formation by the double patterning technique, the wiring extending in one direction is formed in some cases. In this case, the multilayer wiring structure is sometimes formed as wirings extending alternately in X- and Y-directions perpendicular to each other such that, for example, the first layer extends in the X-direction and the second layer extends in the Y-direction.
However, in the case of forming the power supply wiring, for example, in the first layer extending in the X-direction using the double patterning technique as described above, the second layer on the first layer is formed to extend in the Y-direction, so that the support wiring for the power supply wiring cannot be formed in the second layer.